In France, the strong storms of recent decades and their impact on coastlines have led to the emphasis being placed on the causal links that may exist between climate change and the current trends in the coastlines subject to erosion and submersion. However, it seems necessary to put into perspective contemporary geomorphological dynamics in the context of their long-term development. Some examples of coastal developments in Brittany thus make it possible to recall that the mobility of the coastlines is a process that operates at different scales of time and space, between the Flandrian transgression behind the establishment of the current coastlines, historical changes in shoreline lines and coastal forms subject to weather and marine phenomena, changes in sedimentary balances and human intervention. Therefore, in terms of coastal risk management, the envisaged consequences of climate change appear to be aggravating factors in areas that are already very vulnerable, owing in particular to the proliferation of challenges.